The Lubavitcher Rebbe: Reincarnation:

Igros Kodesh (Letters) of the Lubavitcher Rebbe, (Vol 5, Letter 1257):

You tell me you are giving the proper amount of Tzedakah. However, your shalom bayis (peace in the home) situation, needs great improvement.

The fact that you are having great difficulties in this area is a sign, that this Mitzvah has not been completed in your previous life.
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The holy Arizal teaches us, that most souls living in a body, have been here before. The reason they come back again, is to fulfill those Mitzvahs, that they did not do properly the first time around.

Those Mitzvahs that they did complete in their previous lifetime, do not require any more refinement, and therefore their observance is easy.

However, those Mitzvahs that one did not complete in his previous lifetime, are the ones most difficult to do. The Yetzer Hara targets these non-completed Mitzvahs, as the ones to oppose most.
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The fact that the issue of Shalom Bayis is so difficult for you proves, that it is a Mitzvah which needs fulfillment. In your past lifetime, you did not refine this Mitzvah, now is your opportunity.